1. Field of the Invention
This invention relates to a pulse combustor apparatus that utilizes the excitation of sound waves to intensify combustion of a fuel, and further, to increase thermal efficiency, improve heat transfer, reduce pollutants formation and slagging. More particularly, this invention relates to a pulse combustor capable of burning either solid, liquid or gaseous fuels whereby the generated hot, pulsatile flow of combustion products can be used for varying applications such as steam raising for power generation, water heating, space heating, drying and so on.
2. Description of the Prior Art
In the majority of combustors developed to date, the combustion process occurs under steady state conditions; that is, the pressure in every location in the combustor remains approximately constant with time. The only unsteadiness observed in these combustors is that due to turbulence fluctuations. As a matter of fact, these devices are designed specifically to avoid the excitation of any pressure pulsations within the combustor.
As described in U.S. Pat. No. 4,164,210 to Hollowell, pulse combustion heater systems have been known for many years. In such conventional devices, the fuel and combustion air are admitted into a pulse-combustion chamber where they are ignited to produce an internal explosion. The pressure rise associated with the explosion results in the expulsion of the hot combustion products from the chamber, through a tail pipe into an exhaust decoupling or an expansion chamber. This results in the establishment of a negative pressure in the chamber. Consequently fresh air and fuel are drawn into the chamber through appropriate valves, whereupon the next ignition and explosion occurs, followed by closure of the valves until the next negative pressure occurs. Accordingly, once started, a self-perpetuating series of heat-releasing explosions are produced, with combustion air and fuel being ingested automatically and intermittently through appropriate air and inlet valves as needed.
The existing combustors that also burn fuels under pulsatory conditions differ from the present invention by utilizing different combustor configurations and different scientific principles for exciting the pulsations. Furthermore, these combustors were generally designed to burn either gaseous or liquid fuels. The known literature does not disclose the existence of any pulsating combustor that is capable of burning unpulverized solid fuels stably over a sustained period of time.
Prior pulse combustion heater systems are also known from the following U.S. Pat. Nos. 3,267,985 to Kitchen; 3,721,728 to Luetzelschwab; 4,241,723 to Kitchen; and 4,259,928 to Huber.